Resolution, identification, and stability of broadband acoustic arrivals in Fram Strait

TitleResolution, identification, and stability of broadband acoustic arrivals in Fram Strait
Publication TypeJournal Article
Year of Publication2017
AuthorsSagen H., Worcester P.F, Dzieciuch M.A, Geyer F., Sandven S., Babiker M., Beszczynska-Moller A., Dushaw B.D, Cornuelle B.
JournalJournal of the Acoustical Society of America
Volume141
Pagination2055-2068
Date Published2017/03
Type of ArticleArticle
ISBN Number0001-4966
Accession NumberWOS:000398962500088
Keywords1000-km range; aperture vertical array; dependent sound channels; greenland sea; long-range; marginal ice-zone; ocean; propagation; time sensitivity kernels; tomography
Abstract

An ocean acoustic tomography system consisting of three moorings with low frequency, broad-band transceivers and a moored receiver located approximately in the center of the triangle formed by the transceivers was installed in the central, deep-water part of Fram Strait during 2010-2012. Comparisons of the acoustic receptions with predictions based on hydrographic sections show that the oceanographic conditions in Fram Strait result in complex arrival patterns in which it is difficult to resolve and identify individual arrivals. In addition, the early arrivals are unstable, with the arrival structures changing significantly over time. The stability parameter a suggests that the instability is likely not due to small-scale variability, but rather points toward strong mesoscale variability in the presence of a relatively weak sound channel as being largely responsible. The estimator-correlator [Dzieciuch, J. Acoust. Soc. Am. 136, 2512-2522 (2014)] is shown to provide an objective formalism for generating travel-time series given the complex propagation conditions. Because travel times obtained from the estimator-correlator are not associated with resolved, identified ray arrivals, inverse methods are needed that do not use sampling kernels constructed from geometric ray paths. One possible approach would be to use travel-time sensitivity kernels constructed for the estimator-correlator outputs. (C) 2017 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license.

DOI10.1121/1.4978780
Student Publication: 
No